A bomb targeting former Interior Minister Fernando Londoño killed five people and wounded 29 others Tuesday in Bogota just hours after a car bomb was disarmed and Colombia's free trade agreement with the United States took effect.

The bomb was set off to kill Londoño, who served as interior minister from 2002 to 2004 under former President Alvaro Uribe, President Juan Manuel Santos said.

Londoño was wounded, but he is out of danger, Santos, who served as defense minister in Uribe's Cabinet, said.

"I have just learned that Dr. Londoño was the target of an attack on his armored vehicle. Fortunately, Dr. Londoño is in stable condition, but, unfortunately, his driver and a police officer, who were part of his security team, died," the president said in an address to the nation.

The death toll may rise given the condition of some of the people wounded in the bombing, officials said.

Londoño's vehicle was going through a busy intersection in the northern section of Bogota, near the financial district, when the bomb exploded.

Bogota Mayor Gustavo Petro went to the scene, where chaos reigned for hours as ambulances and other emergency vehicles came and went.

"The politics of hatred and vengeance want to rule in Bogota," Petro said, adding that the bomb did not go off in an empty bus as initially reported.

The blast destroyed the bus and several other vehicles, and it damaged nearby buildings and businesses, an Efe reporter confirmed during a tour of the area.

Central University and Sergio Arboleda University, both located near the scene of the attack, were evacuated immediately, while officials banned motorcyclists from carrying riders.

Classes were suspended at other universities in Bogota due to the protests at some institutions, such as the National University, against the free trade agreement.

"I want to condemn this attack in the most emphatic way possible, we do not understand the reason," Santos said.

The attack occurred a few hours after bomb specialists disarmed a car bomb outside the Metropolitan Police headquarters.

Officials said the Revolutionary Armed Forces of Colombia, or FARC, guerrilla group was behind the car-bomb attempt on the police headquarters.

The bombing happened on the day that the U.S.-Colombia Free Trade Agreement, which was signed six years ago by Uribe and former U.S. President George W. Bush, took effect.

President Santos planned to attend a ceremony in the Caribbean city of Cartagena, marking the occasion by seeing off the first ship to sail for the United States with a cargo of textiles.

The president cancelled all his appearances after the attack.

The bombing "is an attempt to tarnish the (image of the) city on the day the FTA takes effect," Petro said.